Thermosetting hydroxyl-containing resinous coating materials usually contain a cross-linking component, such as a phenolic resin, an aminoplast resin or a polyisocyanate; for epoxy resins also polyamines, polycarboxylic acids and anhydrides thereof have found wide-spread use; curing catalysts are often added to reduce curing time and/or temperature. Curing times of up to 1/2 hour and curing temperatures of up to 200.degree. C. are for many purposes acceptable in the thermosetting coating field. The cross-linking component reacts during stoving with hydroxyl and/or epoxy groups of the main resinous binder component, and the cross-linking provides a coating which is insoluble and infusible, and therefore resistant to solvents and elevated temperatures.
Another type of coating materials contain an air-drying binder, which can cross-link through carbon-carbon double bonds, in contact with oxygen; drying accelerators are here some metal salts, such as cobalt and mangenese naphthenate.